None
Not applicable.
The present invention generally relates to product marking and identification and more particularly to a much improved industrial stamp pad printing system.
There is a need to piece identify many products with variable (changeable) information. Pad printing such products with an ink pattern is a proven low cost, aesthetically pleasing marking technique, which produces high contrast, durable marks. Unfortunately, the markings provided by traditional pad printed markings are difficult and/or slow to change, because they create the image using either an etched pattern in a clichxc3xa9 or a pre-formed stamp. Increasingly, there is an identified need to produce unique stamped ink indicia upon each product piece and to change the indicia pattern quickly.
As an example as to how conventional stamp pad printing techniques work, reference is made to U.S. Pat. No. 4,905,594. In particular, FIG. 7 of this patent is reproduced as FIG. 1 herein. A silicone rubber pad, 72, is used to imprint a product (not shown) when it is in a lowered position. The image to be imprinted is etched into a clichxc3xa9 plate, 69, at a surface, 70, which retains ink from a reservoir, 1, when it is extended to the leftmost position (dashed lines). Pad 72 then lowers to pick up the ink resident in the etched area, the clichxc3xa9 is retracted, and pad 72 then extends to the bottommost position to apply the image onto the product.
Clichxc3xa9 plate 69 must be changed if the ink pattern is to be changed. This is a time consuming, manual process, because ink reservoir 1 must be manually removed (clamped and inverted as is detailed in U.S. Pat. No. 5,694,847) prior to changing clichxc3xa9 plate 69. This process, then, must be reversed to install a new clichxc3xa9 plate bearing a new image.
Thus, there exists a need in the art for a stamp marking apparatus wherein the pattern can be changed rapidly and easily so that variable on demand information can be imprinted. It is to such a need that the present invention is addressed.
A method for imaging a product with a pattern commences by forming a film of a wet or tacking marking material on a clichxc3xa9. A negative of the pattern is ablatively imaged into the film on the clichxc3xa9. The negative image then is pressure transferred from the clichxc3xa9 onto a marking pad. Finally, the negative image is pressure transferred from the marking pad onto the product. Preferably, the clichxc3xa9 where the film is formed contains recesses.
The apparatus for practicing the instant method has a moveable clichxc3xa9 having a recessed pocket. An ink reservoir transfers ink into the recessed pocket. A laser imaging system images a pattern into ink contained in the recessed pocket. A stamp pad moves from a home position to contact the imaged pattern for pressure transferring the pattern onto the stamp pad, and then moves to a printing station to pressure transfer the pattern onto a product.
Advantages of the present invention include the ability to pressure print products rapidly. Another advantage is the ability to vary the pattern easily without interrupting the production line. These and other advantages will be apparent to those skilled in the art based on the disclosure set forth herein.